268 resultados para HPLC-ESI-MSn


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This study sought to determine the main components (saccharides and phenolic acids) in crude extract of the Chinese herb Tanshen by electrospray ionization Fourier transform ion cyclotron resonant mass spectrometry (ESI-FT-ICR-MS) in negative-ion mode. Eleven compounds were identified as phenolic acids by exact mass measurement and further confirmed by sustained off-resonance irradiation (SORI) CID data. In addition, monosaccharicles and oligosaccharides (n = 2 similar to 5) and a serial of corresponding anionic adducts of saccharide were observed without adding any anions additionally to the extract solution, and the anionic components were unambiguously identified as H2O, HCl, HCOOH, HNO3, C3H6O2, H2SO4 and C5H7NO3 according to the exact mass measurement results.

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对12批不同来源的刺五加叶提取物进行指纹图谱研究,并利用ESI-MS指纹图谱鉴别刺五加叶与山楂叶。分别采用高效液相色谱(HPLC-UV)和电喷雾电离质谱(ESI-MS)测定12批不同来源的刺五加叶提取物,利用ESI-MS技术测定刺五加叶与山楂叶提取物,得到了分离度、精密度和重现性均较好的刺五加叶HPLC-UV及ESI-MS指纹图谱;同时,利用刺五加叶与山楂叶ESI-MS指纹图谱的差异,成功鉴别了二者,可为刺五加叶药材的质量控制提供参考。

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目的:考察大黄、黄柏、赤芍炮制前后化学成分在质和量方面的变化,以探讨中药的炮制机理。方法:利用电喷雾质谱法(ESI-MS)和高效液相色谱法(HPLC-UV),对大黄、黄柏、赤芍炮制前后的化学成分进行详细研究。质谱:电喷雾电离源(ESI),加热毛细管温度为200℃,喷雾电压为4.5kV;液相色谱:色谱柱为Agilent Zorbax C18柱(4.6mm×150mm,5μm),柱温均为28℃。结果:大黄经酒制和醋制后,其化学成分的含量变化较大;黄柏经酒制后巴马汀的含量略有增加,而小檗碱的含量呈下降趋势;盐制对于黄柏的化学成分几乎无影响;赤芍经酒制和炒制后,芍药苷的含量都呈下降趋势。结论:不同炮制方法对化学成分的影响不同,为进一步阐明中药材炮制入药的科学内涵提供了实验依据。

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A new labeling reagent, 1-(2-naphthyl)-3-methyl-5-pyrazolone (NMP), coupling with liquid chromatography (LC) with electrospray ionization mass spectrometry (ESI-MS) for the detection of carbohydrates from a famous Tibetan medicine is reported. Carbohydrates were derivatized to their bis-NMP-labeled derivatives. The method, in conjunction with a gradient elution, offered a baseline resolution of carbohydrate derivatives on a reversed phase Hypersil ODS-2 column. The carbohydrates such as mannose, galacturonic acid, glucuronic acid, rhamnose, glucose, galactose, xylose, arabinose, and fucose could be successfully detected by UV and ESI-MS. Derivatives showed intense protonated molecular ion at m/z [M+H]+ in positive ion mode. The mass to charge ratios of characteristic fragment ions at m/z 473.0 could be used for the accurately qualitative identification of carbohydrates; this characteristic fragment ion was from the cleavage of C2-C3 bond in the carbohydrate chain giving the specific fragment ions at m/z [MH-CmH2m+1Om-H2O](+) for pentose, hexose, and glyceraldehydes, and at m/z [MH-CmH2m-1Om+1-H2O](+) for alduronic acids, such as galacturonic acid and glucuronic acid (m=n-2, n is carbon atom number of carbohydrate). Compared with the traditional 1-phenyl-3-methyl-5-pyrazolone (PMP) reagent, currently synthesized NMP show the advantage of higher sensitivity to carbohydrate compounds with UV and ESI-MS detection.

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The antibacterial drug furazolidone belonging to the group of nitrofuran antibacterial agents has been widely used as an antibacterial and antiprotozoal feed additive for poultry, cattle, and farmed fish in China. During application a large proportion of the administered drug may reach the environment directly or via feces. Although the use of furazolidone is prohibited in numerous countries, there are indications of its illegal use. It is known that furazolidone can be rapidly metabolized to 3-amino-2-oxazolidinone (AOZ) in the body of the target organism. In this study, a total of 21 fish feed samples, including 17 commercial fish feeds from local markets in China (representing 15 different formulations) and 4 fish feeds obtained from Germany and Turkey, respectively, are analyzed to determine whether the drug is still illegally used or commercially available feeds are contaminated by this drug. High-performance liquid chromatography (HPLC) and liquid chromatography-electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS) methods have been implemented to determine furazolidone and its metabolite AOZ in fish feeds containing animal protein, respectively. An efficient and convenient cleanup method for the determination of furazolidone in fish feeds is developed, and a simple cleanup method for the determination of AOZ is used. Method recoveries for samples used were determined as 87.7-98.3% for furazolidone at two spike levels of 2.0 and 5.0 ng g(-1) and as 95.6-102.8% for AOZ at spike levels of 0.4 and 0.8 ng g(-1). Limits of detections were 0.4 ng g(-1) for furazolidone and 0.05 ng g(-1) for AOZ. The established methods are therefore suitable for the determination of furazolidone and its metabolite AOZ in fish feeds at trace contamination levels. Using the established methods, all fish feed samples have been proved to be furazolidone negative; however, AOZ is tested in 16 of 17 fish feeds obtained from local markets in the Hubei province of China, with a positive rate as high as 94.1%.

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A new HPLC-APCI/MS method for the identification of ginsenosides has been developed. The analyses were performed on a reversed-phase C-18 column using a binary eluent (acetonitrile and water) under gradient conditions. Although APCI is a high-temperature evaporative process, HPLC-APCI/MS could effectively identify thermo-labile ginsenosides. The [M-H](-) ions and the thermal degradation ions of ginsenosides could be clearly observed under negative and positive ion conditions, respectively, and these were used to identify the molecular masses, the aglycone structures and the sugar groups of ginsenosides. APCI/MS can provide more explicit information than ESI/MS for identifying and distinguishing ginsenosides. Using the HPLC-APCI/MS method, 35 ginsenosides were identified in Panax ginseng. Copyright (C) 2005 John Wiley & Sons, Ltd.

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A monolithic enzymatic microreactor was prepared in a fused-silica capillary by in situ polymerization of acrylamide, glycidyl methacrylate (GMA) and ethylene dimethacrylate (EDMA) in the presence of a binary porogenic mixture of dodecanol and cyclohexanol, followed by ammonia solution treatment, glutaraldehyde activation and trypsin modification. The choice of acrylamide as co-monomer was found useful to improve the efficiency of trypsin modification, thus, to increase the enzyme activity. The optimized microreactor offered very low back pressure, enabling the fast digestion of proteins flowing through the reactor. The performance of the monolithic microreactor was demonstrated with the digestion of cytochrome c at high flow rate. The digests were then characterized by CE and HPLC-MS/MS with the sequence coverage of 57.7%. The digestion efficiency was found over 230 times as high as that of the conventional method. in addition, for the first time, protein digestion carried out in a mixture of water and ACN was compared with the conventional aqueous reaction using MS/MS detection, and the former solution was found more compatible and more efficient for protein digestion.

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水母雪莲(Saussurea medusa Maxim.)和新疆雪莲(Saussurea involucrata Karel. et Kir.)是我国珍稀的药用植物资源,具有清热解毒、止痉镇痛、敛伤、消肿及治疗热病、风湿等多种功效。雪莲的主要药用成份为紫丁香甙(Syringin)、芦丁(Rutin)、高车前素(Hispidulin)和Jaceosidin等苯基丙酸类(phenylpropanoid)和黄酮类(flavonoids)物质。最新的药理研究表明,上述物质还具有抗菌消炎、保肝降压、延缓衰老和抑制癌细胞增殖等重要的研发价值。 雪莲生境恶劣,生长缓慢,人工引种困难,加上长期掠夺性采挖,已使雪莲处于灭绝的边缘。为了保存国家珍稀植物品种,保护生态环境,满足临床上对雪莲药物的需求,本研究在雪莲组织培养的基础上,应用诱导子添加技术和毛状根培养技术对雪莲中具有重要药用价值的次生代谢物质进行调控,并对雪莲MYB类转录因子的功能进行了初步探索,为保护珍稀植物资源、维护生态环境、开发野生雪莲替代产品、缩短雪莲药用成份的生产周期奠定了基础。另外,分析了野生雪莲和雪莲培养物中主要生物活性成份的种类及含量,为今后雪莲药理药效研究及品质评价奠定了基础。 为了提高雪莲黄酮的产量,满足工业化生产的需要,在细胞培养水平上,通过添加茉莉酸甲酯(MJ),对雪莲黄酮类物质的代谢进行调控。研究了诱导子的添加时间、添加浓度对水母雪莲红色系悬浮细胞的生物量和总黄酮产量的影响。发现在细胞培养的指数期(第9天)添加5.0 µmol/L的MJ,可以使总黄酮产量提高2.4倍(1134.5 ± 63.86 mg/L),而雪莲细胞干重(dw)仅比对照提高23.8 %(20.4 ±0.27 g/L)。另外,细胞中苯丙氨酸裂解酶(PAL)的活性分析表明,MJ添加后PAL活性的增加与雪莲总黄酮含量增长之间存在相关性。 在器官培养水平上,对雪莲毛状根的诱导频率及其培养条件进行了研究。结果表明,选择发根农杆菌R1601侵染预培养2天的新疆雪莲根段外植体,毛状根的诱导效率可达到83 %。毛状根的冠瘿碱检测、PCR和Southern分析表明,Ri质粒中的T-DNA已整合到植物基因组中并稳定表达。以新疆雪莲毛状根为外植体,能够容易地获得再生芽。在含有1.0 mg/L 6-BA的MS固体培养基上,其再生频率高达91 ± 5.9 %,是其正常根的2.4倍。而水母雪莲在该培养条件下,仅有少量的畸形芽出现。进而对毛状根的培养条件进行初步研究,结果表明在无激素附加的MS液体培养基中,新疆雪莲的HR1601根系在一个培养周期内(32 天),其生物量能够达到接种量的16倍,而紫丁香甙含量(43.5 ± 1.13 mg/g dw)能够达到野生雪莲的83倍。从而显示了雪莲毛状根培养体系的优良特性。 在基因水平上,对雪莲黄酮类物质代谢调控的研究已经展开。玉米P基因编码的Myb类转录因子能够调节黄酮类物质代谢途径关键酶基因的表达。根据P基因的保守序列设计引物,从雪莲细胞培养物中获得了SmP基因。核酸序列分析表明,SmP基因与烟草中涉及苯丙素类物质代谢途径的LBM 1、LBM 3和MybAS 1基因具有较高的一致性,分别为66 %、60 %和61 %。因此为了研究雪莲SmP基因的功能,构建了正义表达载体,并与先前构建好的反义表达载体分别导入烟草,分析了转基因植株的形态特征及黄酮类物质的含量变化。其中,约有30 %转反义SmP基因的株系表现叶片皱缩、叶脉紊乱、主侧脉角度缩小、叶片、花瓣失去对称性以及花粉败育等性状。 另外,通过正交试验设计优化了雪莲提取工艺的条件,并对雪莲细胞提取物进行了分离纯化。正交试验设计结果表明,温度对雪莲黄酮提取效率的影响极为显著,而分批多次提取比一次性浸提,能够收到较好的提取效果。考虑到工业生产中的实际问题,推荐在60 ℃水浴条件下,采用50 %乙醇对雪莲样品连续浸提2次的方案。对雪莲提取物的纯化研究表明,雪莲成份复杂,仅依靠单一的分离手段,往往难以奏效。另外,野生雪莲及雪莲培养物中生物活性成份的比色法、HPLC(High Performance Liquid Chromatography)、LC-ESI-MS(Liquid Chromotagraphy Electrospray Ionization Mass Spectrometry)分析表明,传统的NaNO2-AlCl3 法测定雪莲总黄酮的含量,结果偏高,不利于雪莲黄酮的实验室研究分析与今后工业化生产的质量监控。而AlCl3 法的显色反应较为特异,今后有望取代NaNO2-AlCl3 法,作为雪莲类药材品质评价的标准。而HPLC-DAD结合LC-ESI-MS可以对雪莲中的主要生物活性成份进行较为准确的定性分析,从而解决了由于缺乏相应的雪莲化合物标准品而难以对雪莲中的成份进行定性定量分析及比较的难题。最后综合利用上述分析方法,对雪莲细胞培养物中的花素类物质进行了分析。结果表明,雪莲细胞中至少含有7种花色素类物质,分别为矢车菊素-3-O-葡萄糖甙及其衍生物、天竺葵素糖甙衍生物和芍药色素糖甙衍生物。

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本文通过对蓝细菌Synechocystis sp. PCC 6803在添加葡萄糖、Na2S203的BG-11培养基中的生长特性、脂类及脂肪酸组成、细胞低温荧光、色素组成进行分析测定,总结出如下规律: 当蓝细菌Synechocystis sp. PCC 6803在添加有葡萄糖的BG-11培养基中培养时细胞出现了一种新的糖脂(记为糖脂-x),在添加果糖、麦芽糖、乳糖等其它碳源的培养基中生长的细胞中也检测到糖脂-x糖脂-x的出现经推测是与活性氧相作用的产物,当在含糖的培养基中加入活性氧猝灭剂Na2S203时能有效地抑制糖脂-x的出现。糖脂一x的出现伴随着其它脂、尤其是双半乳糖甘油二酯(DGDG)的含量下降,这可能与细胞营养代谢类型的转变相适应。糖脂-x的出现使细胞适应异养生长条件,这时藻胆体(PBS),光系统II(PSII),光系统I(PSD降解,叶绿素消失。 糖脂-x经1H-NMR波谱术检测证实为甘油糖脂,经气质联谱分析其脂肪酸组成中含大量的枝链脂肪酸,12-甲基十四碳酸、12-甲基十五碳酸、12-甲基十六碳酸以及两种稀有的含氮脂肪酸。这些脂肪酸在添加高浓度葡萄糖的培养基中生长的.Synechocystis sp. PCC 6803中的单半乳糖甘油二酯(MGDG)也能检测到。ESI-MS以及P-SI-MS测定结果表明糖脂.x含一分子的脂酰基侧链以及两分子的己糖,半乳糖与葡萄糖。 对.Synechocystis sp. PCC 6803生长在不同浓度的葡萄糖与Na2S203培养基中脂类组成与脂肪酸组成进行比较,发现Na2S203能有效地增加膜脂中硫代异鼠李糖二酰基甘油(SQDG)和磷脂酰甘油(PG)的百分含量,培养基中同时添加葡萄糖时能抵消Na2S203的这一效应。此外,Na2S203能显著增加单半乳糖甘油二酯(MGDG)、双半乳糖甘油二酯(DGDG)中十六碳酸(C16:0)的百分含量,这一效应也能为葡萄糖恢复。Na2S203不能显著地改变SQDG中C16:0的百分含量,加入葡萄糖时能降低C16:0的百分含量。这些结果说明Na2S203可能充当一种还原剂使膜脂处于一种低的不饱和状态,同时加入葡萄糖时能降低Na2S203的还原力。此外,Na2S203还可作为SQDG合成中的硫供体。 用HPLC测定.Synechocystis sp. PCC 6803在添加不同浓度的Na2S203,葡萄糖的BG-11培养基中生长时的叶绿素与类胡萝卜素浓度,结果表明葡萄糖表现出对叶绿素与类胡萝卜素水平的抑制效应,Na2S203在低浓度时表现出对叶绿素与类胡萝卜素水平的促进效应,但在高浓度时表现出抑制效应。因此适当浓度的Na2S203的加入有利于维持蓝细菌在培养基中添加葡萄糖的生长条件下的低水平自由基,能使葡萄糖表现出促进细胞生长的特性。 通过测定Synechocystis sp. PCC 6803生长曲线中葡萄糖、Na2S203的浓度效应,结果表明葡萄糖在低浓度(例如5 mmoI.L-l)时表现出促进细胞的生长,在相对高的浓度表现出抑制细胞生长的效应。在培养基中同时加入Na2S203时可恢复葡萄糖对细胞的生长的促进效应。单独加入Na2S203表现出对细胞生长的抑制效应。这说明葡萄糖、Na2S203对细胞的生长存在着正的协同效应。

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采用固相微萃取(SPME)高效液相色谱法(HPLC)同时测定了水中苯酚、4-硝基酚、3-甲基酚、2,4-二氯酚、2,4,6-三氯酚、五氯酚等六种酚类化合物的含量.采用ZORBOX SB-C18柱,以甲醇-1%乙酸水溶液为流动相进行梯度洗脱,流速为1.0 mL/min.紫外检测波长为254、280 nm.六种酚类化合物的检出限为0.31~1.90μg/L,加标回收率为88%~103%.该方法操作简单,能快速、准确地检测水中的酚类化合物.

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A novel bradykinin-potentiating peptide (BPP), designated as TmF, has been purified to homogeneity from the venom of Trimeresurus mucrosquamatus by 70% cold methanol extraction, Sephadex G-15 gel filtration and reverse-phase high performance liquid chromatography (RP-HPLC). The amino acid sequence of TmF was determined to be pGlu-Gly-Arg-Pro-Leu-Gly-Pro-Pro-Ile-Pro-Pro (pGlu denotes pyroglutamic acid), which shared high homology with other BPPs. The molecular mass of TmF was 1.1107 kD as determinated by electrospray ionization-mass spectrometry (ESI-MS), which was in accordance with the calculated value of 1.1106 kD. The potentiating "unit" of TmF to bradykinin-induced (BK-induced) contraction on the guinea-pig ileum in vitro was (1.13 +/- 0.3) unit (mg/L), and TmF (5.0 x 10(-4) mg/kg) increased the pressure-lowering-effect of bradykinin (5.0 x 10(-5) mg/kg) with approximate descent value of (14 +/- 2) mmHg. In addition, TmF inhibited the conversion of angiotensin I to angiotensin 11, 2 x 10(-3) mg of TmF caused 50% inhibition (IC50) of angiotensin-converting enzyme (ACE) hydrolyzing activity to bradykinin.

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用高效液相色谱 (HPLC)法研究了武汉东湖周年及围隔实验水柱颗粒物色素的组成及变化。共检测到约 2 0种色素 ,类胡萝卜素含量较高的有硅藻的标志色素岩藻黄素 ,隐藻的异黄素 ,蓝、绿藻的黄体素、玉米黄素及胡萝卜素。东湖叶绿素a的代谢产物主要为脱植基叶绿素a(全湖年均约占叶绿素a的 5 % ) ,而非脱镁叶绿素a或脱镁叶绿酸a。围隔实验结果表明 :叶绿素a与总浮游植物 (r =0 .84) ,叶绿素b与绿藻 (r=0 .77) ,岩藻黄素与硅藻 (r =0 6 8) ,异黄素与隐藻生物量 (r=0 .83